Process for producing substantially pure magnesium



June 23, 1936. F. HANSGIRG PROCESS FOR PRODUCING SUBSTANTIALLY PURE MAGNESIUM 2 Shgets-Sheet 1 4 5 9 l 5 2 v I 1 m. A d e l 1 F 5:31 238g Q T INVENTOIZ. z

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Patented June 23, 1936,

PROCESS FOR PRODUCING SUBSTAN- TIALLY PURE MAGNESIUM Fritz Hamill! Radentheln, Austria, assignor to American Magnesium Metals Corporation,

Pittsburgh, Pa, a corporation of Delaware Application April 25, 1934, Serial No. 722,278

In Austria Mar so, 1933 6 Claims. (01. 75-17) My invention relates to a process and apparatus for producing substantially pure magnesium.

One object of the invention is to separate sub-' stantially pure magnesium from non-volatile concomlttant substances. As to this subject matter, the instant case is a continuation in part of my prior applications Serial No. 655,067, filed February 3, 1933; and Serial No. 693,470, filed 10 October 13, 1933 which case is a division or the aforesaid application Serial No. 655,067.

Another object. of the invention is to enable magnesium to be distilled so as to recover the distillate in the form of globular grains.

It has already been proposed to separate magnesium from non-volatile impuritiesby vacuum] distillation, and to condense the vapors in the form of a liquid deposit. In accordance with the present invention the liquid condensate is caused to drop into a hydrocarbon oil. 'By virtue of this step the distillation yields directly pure metallic magnesium in granular form, contaminating foreign matter being taken up by the hydrocarbon oils, which do not mix with the molten metal,

and are thus eliminated. The magnesium is thus not only recovered in the course of the distillation process itself, in the granular form which is particularly well suited for many purposes, but also further refined during solidification, the

latter being a feature of particular importance, since dusty impurities are always carried over by the metallic vapors evolved in distillation.

Moreover, the possibility is afforded of removing the refined magnesium grains together with the oil from the receiver, by means of a lock chamber, thus simplifying the removal ot-the magnesium from the still apparatus--a point of special importance when the distillation is carried out under reduced pressure.

4 The contamination of the disengaged metallic vapors by dusty impurities carried over by these vapors in the distillation is a source of particular inconvenience when magnesium is to be worked-up that is in itself in the state oi dust.

Dust of this nature is formed, as an undesired byproduct, in the refining of compact metallic magnesium by distillation. Moreover, in the course of producing magnesium by heating magnesium oxide with a reducing agent and suddenlyrchilling the cooled vapors, magnesium in the form of fine powder was intentionally obtained asthe final product of the process.

Later on, according to my invention disclosed and claimed in the application Ser. No. 518,915,

filedFebruary 27, 1931, now Patent No. 1 943,601,

condensing the magnesium vapors to the state of dust was systematically embodied as part of a two-stage process for the recovery of compact metallic magnesium by reduction of oxidic compounds of magnesium, in the first stage of which 5 process the said compounds are reduced with carbon at a temperature above the boiling point of metallic magnesium, and the generated magnesium vapors condensed to the state of dust, by

chilling, whereas in the second stage the finely 10 divided magnesium thus obtained is then vaporized for the purpose of condensing'the vapor to compact metallic magnesium. The magnesium dust formed in the first stage of the said process consists of a mixture of magnesium oxide 15 and carbon in which the metallic magnesium is in colloidal distribution. In converting such magnesium dust into compact metallic magnesium by distillation, which step forms the second stage of the process, the method according to the 20 present invention plays a highly useful part. Even if the vapors issuing from the distillation zone are passed into the condensation zone through an interposed dust removing device (e,

g. a cyclone separator as is disclosed and claimed 5 v in my prior application Serial. No. 704,298, filed December 28, 1933) a residual portion of dusty impurities will yet find its way into the condensation chamber.

The present invention affords the possibility 30 of completely eliminating these residua. By collecting the liquid condensate under a layer of hydrocarbon oil, granulated, refined magnesium,

in the form of silvery globular grains (10 to 20 mm. in diameter), containing not more than 35 0.019% of impurities, can be obtained direct from the impure dust.

The present method does not require hydrocarbon oils of any special character, high-boiling mineral oil distillation products of slight 40 viscosity and relatively high flash point, such as for example transformer oil or light spindle 011, being applicable to the present purpose.

The distillation concerned is advantageously carried out in a distilling chamber which is con- 5 nected, through a heated conduit, with a hollow vessel the upper portion of which is heated where- .as the lower portion is not heated, and which contains in, its upper portion a"condenser, and i'orms in its lower portion a receiver provided with 50 a discharging device. More specific details will appear from the detailed description given below in connection with the accompanying drawings which illustrate diagrammatically and by way of example a typical embodiment of apparatus suitable for use in carrying out the method according to the present invention.

In said drawings Fig. 1 is a front elevation of the entire apparatus partly in vertical section; Fig. 2, ohm enlarged scale, a vertical section on the line II-'-II, Fig.1; and Fig. 3, a detail in cross section on the line III-III, Fig.- 2.

Like reference characters denote like parts in the several figures of the drawings.

According to the example shown in Figs. 1 to 3, the distillation chamber i is in the form of a tube, which extends through a suitable heating apparatus, such as an electric radiation furnace 2. The material to be distilled is placed in the charging hopper 3 and passes through the lock chamber 4-the closure members 5 and 6 coacting with levers-into a stock vessel 1, from which it is continuously red, by means or a worm 8 or the like, into the distillation chamber I, through which the material is conveyed by means or a worm 9 or the like. The residue falls into a collector ID, from which it is discharged through a lock chamber II, with the closure members 5* and 6". The collector Ill and chamber II, as also the chamber 4 and stock vessel I, are connected with a vacuum pump by means of pipes adapted to be closed independently.

A pipe i2 (Fig. 2) issues from the middle of the distillation chamber I, said pipe debouchlng tangentially into a cylindrical dust precipitating chamber l3, which tapers conically in a downward direction. The lower end of the chamber is connected with the dust collecting space M. The vertical limb of a bent pipe I! passes through the centre of the cover of the chamber II and constitutes the connection between said chamber and the cylindrical hollow vessel It. 4

The dust contained in the vapors which enter the dust-removing chamber I3 is precipitated chiefly on the cylindrical jacket or the chamber by the action of centrifugal force and falls into the collecting space M, whilst purified vapors pass on to the condenser via' pipe ii. In the upper portion of the vessel It the condenser I1 is fitted in such a manner that the incoming vapors bathe the lower-most portion of the cooling surface. The pipe I8 leads to the vacuum pump. The lower portion of the hollow vessel passes through the heating chamber 2, and may even be cooled, by means of suitable auxiliary devices that are not represented in the drawing.

The bottom of the hollow vessel is tapered and opens into a discharging device which permits 01 the withdrawal or the distillate without breaking the vacuum. In the embodiment shown, this purpose is served by the chamber is which is 'fitted with the valves 20 and 2| and which forms a lock for the discharge of the solidified material. This lock chamber may be replaced by any other known discharging device, such as a barometric receiver for vacuum distillation. The

' lower portion of the hollow vessel I6 is connected with the suction side of a pump 22 by -means of a tube 23 and forms a receiver which is charged with hydrocarbon oil. The delivery side oi. the

pump 22 is connected, through a tube 24 with a filter 25 from which the refined liquid discharges into a stock vessel 26, whence it is returned to the receiver by way of the pipe line. 21.

' The magnesium vapors entering the hollow vessel iii are condensed on the cooling surface 01 the condenser II to a liquid condensate which drops intou'the hydrocarbon oil below. The metallic granules are lock-discharged, together with oil, by means of the valves 20 and 2|. The circulation of the liquid through the filter 25 efiects the continuous elimination of the impurities taken up by the oil, and prevents undesirable heating of the latter.

I claim:

1. A process oi! separating substantially pure magnesium from non-volatile concomitant substances which comprises vaporizing the magnesium, condensing the vapor into the. form of a liquid deposit, and causing the liquid condensate to drop into hydrocarbon oil, and thereby producing globules of substantially pure magnesium.

2. A process of separating substantially pure magnesium from non-volatile concomitant sub-.

. the liquid condensate to drop into hydrocarbon oil, and lock-discharging the resulting substantially pure metallic granules together with the 1 oil.

3. A process of separating substantially pure magnesium from non-volatile concomitant substances which comprisas vaporizing the magnesium under reduced pressure in contact with a non-oxidizing gas, condensing the vapor into the form of a liquid deposit, causing the liquid condensate to drop into hydrocarbon oil, and lock-discharging the resulting substantially pure metallic granules together with the oil.

4. A process 10': recovering pure metallic magnesium from finely divided magnesium by distillation which comprises heating the magneslierous material to liberate magnesium vapor therefrom, removing the resulting vapor by nonoxidizing gas from the heated zone, condensing the vapor into the form of a liquid deposit, and

hydrocarbon oil, and thereby producing globules lot substantially pure magnesium.

5. A process for recovering pure metallic magnesium from finely divided magnesium by distillation which comprises heating the magnesiferous material to liberate magnesium vapor therefrom, removing the resulting vapor by non-oxidizing gas" from the heated zone, separating out dust from said flowing vapor, condensing the vapor into the form of a liquid deposit, and causing the liquid condensate to drop into a hydrocarbon oil, and thereby producing globules of substantially pure magnesium.

6. A process for recovering pure metallic magnesium from -finely divided magnesium by distillation under reduced pressure, which comprises heating the magnesiferous material to liberate magnesium vapor therefrom, removing the resulting vapor by non-oxidizing gas from the heated zone, separating out dust from said flowing vapor, condensing the .vapor into the form of a liquid deposit, causing the liquid condensate to drop into and to collect under a layer of hydrocarbon oil in the, form of globular grains, and lock-discharging tlie thus formed substantially pure metallic granules together with the oil.

FRI'I'Z HANSGIRG. 

